Gatekeeper are nothing but a device, a token device that are created to act as a gateway for the communication process. They receive user requests from CLI, GUI, or other means, and generate low-level commands (syscalls) that are transmitted into the Symmetrix array for action.
A Syscall(special set of Symmetrix instructions encapsulated as sub-commands and sub-formats of certain standard system operation codes) is a method of accessing and modifying Symmetrix internal states, statistics, and services from external clients, such as host components, APIs, and service processor programs.
Gatekeepers are 3 MB (3 cyl) for Enginuity levels 57xx, 58xx and higher, and 3 MB (6 cyl) for Enginuity levels of 56xx device.Gatekeeper devices are used to facilitate the special communication that controls the Symmetrix array for either requesting tasks be performed or retrieving status.
Following management applications requires gatekeeper access:
* CLI commands to create Gatekeeper device create dev count=x, config=2-way-mir, emulation=FBA, size=6; or symconfigure -sid xxx -cmd "create gatekeeper count=xx,emulation=FBA;" commit *Display gatekeeper device symgate list